would the axles off a zc tranny, 90 integra axles if i recall, fit in the hubs on a 91 4 spd?

 

Assuming that buy "4 spd" you are talking about a STD hatch, then no, they won't. Only HF/STD axles will fit in the HF/STD hubs. If you want to use a ZC tranny, you will need to swap to DX/LX/Si hubs.

You can use the HF/STD axles and hubs if you use any other D-series transmission that doesn't require an intermediate shaft.